1. Field of the Invention
This invention relates to a method for providing a protective surface on various articles, particularly maleic anhydride interpolymer resin moldings. In one embodiment this surface is achieved by forming the ammonium or amine salts of a maleic anhydride-containing interpolymer on the surface of an article, and then heating the article at a temperature sufficient to form the cyclic imide structure.
2. Description of the Prior Art
Resinous polymers are especially useful in a wide variety of thermofabricated articles. Styrene and maleic anhydride copolymers and reinforced composites of these resins have even been considered for replacement of metals in certain applications because they exhibit good modulus and heat distortion temperature (HDT) properties. Because interpolymers of this type are susceptible to attack by strong bases and ketone-containing compounds, the search continues for improved methods of protecting the resin and preventing its degradation.
U.S. Pat. No. 3,669,718 to Chiu et al. describes the coating for such articles which gives protection from the deleterious action of organic solvents. However, a coating which is resistant to attack by strong basic solutions has not been demonstrated.